I’ve recently started getting into bird photography and I thought I’d share my thoughts so far
Telephoto Lenses are a must, I started with a 70-300 that I got right after my first SLR purchase. They can range up to 800mm and above and also have prices as high as you want to go. The advice I keep hearing is purchase the largest telephoto lens you can afford. Another interesting tip I've heard is that generally the smaller the range the better the quality of the lens ie - a 300mm is better than a 70-300 and a 70-300 is better than a 10-3000.
My advice if your cost conscious is to not be afraid of the off brands - sigma and tamron have put out some excellent lenses for much less $$. I'm personally using a Sigma 120-400mm and I've been very pleased with it.
You can also purchase what's called a teleconverter / extender; basically this multiples your zoom by the specified amount (usually 1.4x or 2x), but there is a cost - you lose a bit of light and have to adjust your settings to compensate.
Having a good set of binoculars is also incredibly handy, I didn’t realize this at first since I was so used to looking through my camera lens, but it’s so much faster to lift up the binoculars.
In general the faster your shutter speed the better; I use a handholding rule that I must be at least 1/my zoom so if i’m zoomed to 300mm if i’m not at least shooting at 1/300 or more i need to adjust something. (lower the aperture or raise the ISO)
On the subject of tripods; I started out thinking that you really needed to always use one when birding, but i’ve actually found that as long as the light is good it’s quite possible to go handheld. I actually just purchased a monopod which had excellent reviews on amazon it promises to be much more portable but still offer added stability.
I’d also recommend shooting in AI servo / Continuous Focus mode, especially your subject is in motion.
good places I'vebeen for birding so far:
Huntington Beach at Murrel’s Inlet, SC
Pitt Street in Chareston, SC
Iris gardens in Sumter, SC
Next on my list:
Caw Caw Nature & History Interpretive Center